Effective treatment of perianal tumors in dogs with electrochemotherapy

Background: Electrochemotherapy is an antitumor therapy that utilizes locally-delivered, short intense direct current electric pulse to the tumor nodule plus chemotherapy. The aim of the present study was to evaluate the electrochemotherapy treatment of perianal tumors of different sizes in dogs. Materials and Methods: In 12 dogs, 26 tumor nodules of perianal tumors of different size, and clinically expected to be of different histological type, were treated with electrochemotherapy. Electrochemotherapy consisted of intratumoral injection of cisplatin (1mg/cm(3)) or bleomycin (3mg/cm(3)), followed by application of electric pulses (8 electric pulses; amplitude, 910 V duration, 100,us, frequency, 1 Hz) to the tumor nodule. Results: Responses to treatment were assessed 4 weeks after the therapy; 82% of all tumors treated with electrochemotherapy responded with objective response (OR) (complete response (CR)=41%, partial response (PR)=41%), 16% responded with no change (NC) and 1 tumor (2%) went to progressive disease (PD). At the end of the observation period for each tumor, ranging from 1 to 34 months, 92% OR (CR=65%, PR=27%), 8% NC and no PD were obtained. No major local or general side-effects were noted. Conclusion: Electrochemotherapy with cisplatin or bleomycin is an effective treatment of perianal tumors in dogs. The advantages of this therapy are its simplicity, short duration of treatment sessions, low chemotherapeutic doses and insignificant side-effects, as well as the fact that the subject does not have to stay in hospital.